Pattern 1: Nernst Equation Calculation (High Frequency — NEET 2016–2024)

What is asked: Given E°cell, concentrations of $Zn^{2+}$ and $Cu^{2+}$ (or other pairs), calculate actual cell EMF. Key trap: Writing the wrong Q expression. Always check: which is cathode ($Cu^{2+}$ reduces), which is anode ($Zn^{2+}$ produced). Q = [$Zn^{2+}$]/[$Cu^{2+}$] for Daniell. Template answer: E = E°cell − (0.0592/n) log Q. Identify n from the half-reactions.

Pattern 2: Faraday's Law Mass Deposition (High Frequency — almost every year)

What is asked: Calculate mass of metal deposited given current, time, and n. Key traps:

1. Forgetting to convert minutes to seconds
2. Using n = 1 for Cu (should be n = 2)
3. Using wrong molar mass

Template: Write the half-reaction → identify n → apply w = MIt/(nF).

Pattern 3: Kohlrausch's Law and Λ°m Calculation (Medium Frequency)

What is asked: Find Λ°m of a weak acid (acetic acid) from three given strong electrolyte values. Method: Identify which ions you need; arrange the given electrolytes so that unwanted ions cancel. Template: Λ°m($CH_{3}COOH$) = Λ°m($CH_{3}COONa$) + Λ°m(HCl) − Λ°m(NaCl)

Pattern 4: Assertion-Reason on Galvanic/Electrolytic Polarity (Medium Frequency)

What is tested: Whether student knows anode is negative in galvanic but positive in electrolytic cells. Common incorrect assertion: "Anode is always negative." Correct statement: "Anode reaction is always oxidation in BOTH cell types; only POLARITY differs."

Pattern 5: Electrochemical Series — Feasibility (Medium Frequency)

What is asked: Will reaction X + $Y^{2+}$ → $X^{2+}$ + Y occur? Method: Check if E°($X^{2+}$/X) < E°($Y^{2+}$/Y). If yes, spontaneous. E°cell = E°($Y^{2+}$/Y) − E°($X^{2+}$/X) > 0.

Pattern 6: $\Delta G$° and E° Relationship (Low-Medium Frequency)

What is asked: Given E°cell and n, find $\Delta G$°. Template: $\Delta G$° = −nFE°. Negative $\Delta G$° (kJ) when E°cell > 0.